Key findings

In 2014, New Zealand had 71 identified rare ecosystems, with 45 of them threatened with extinction.

Of the 45 threatened ecosystems, 18 were classified as critically endangered (the highest level of threat), 17 as endangered, and 10 as vulnerable.

Inland and alpine systems had the largest number of rare ecosystems (30), with just over half (16) threatened.

In contrast, 10 of 13 coastal ecosystems and 10 of 15 wetland ecosystems were threatened.

The three rare ecosystems induced (created) by indigenous vertebrates were classified as critically endangered (the highest level of threat). An example is fur seal haul-out sites, where the seals create unique habitats by disturbing plants and animals at places where they exit and enter the water.

Note: Rare ecosystems were identified by expert opinion and represent <0.5 percent of New Zealand’s land area. Ecosystems are grouped into classes for this summary based on Williams et al (2007). The subterranean basalt fields ecosystem (classed as subterranean or semi-subterranean ecosystems) has not been graphed but was classified as data deficient.

Definition and methodology

Rare ecosystems were identified by experts on the basis that they each covered less than 0.5 percent of the land area of mainland New Zealand. The rare ecosystems were subjected to the International Union for the Conservation of Nature’s (IUCN) Red List criteria for ecosystems to classify their threat status (Williams et al, 2007). These assess ecosystems against four criteria:

short-term decline

historical decline

small current distribution or very few locations

very small current distribution.

The assessment criteria are then refined using subcriteria to identify the threat status of each ecosystem. Ecosystems not threatened with extinction are classified as least concern. Least concern indicates there is still a threat to the ecosystem, but it is not currently a conservation priority. Where there is insufficient data to classify an ecosystem, it is classified as data deficient.